Subnanosecond-pumped optical parametric oscillator for near and middle infrared

An experimental investigation was made of the energy, frequency, and spatial characteristics of the resonance wave radiation from a single-resonator optical parametric oscillator (OPO) utilizing an LiJO₃ crystal pumped by a train of pulses of duration τ = 10^–2–1 nsec. When pumped by λ = 0.53 μ radiation, the power of the resonance wave from the OPO reached 12 MW in the 0.61–2.7 μ range. When pumped by λ = 1.06 μ radiation, the radiation power reached 30–50 MW in the 1.4–2.7 μ range. In feedback OPO systems pumped by a sequence of subnanosecond pulses a stable efficiency of several tens of percent was achieved for a resonance wave radiation divergence close to the diffraction limit and a line width Δν ~ 1/τ.